feat: Init; #string ...

- Initialize all property
- Add #string
- Add #to_s to support File#write
- Add write support for #array

Author: DanSnow

src/binary_parser.cr

@@ -18,6 +18,10 @@ class BinaryParser
     save(io)
   end
 
+  def to_s(io : IO)
+    save(io)
+  end
+
   def save(io : IO)
     {% for method in @type.methods %}
       {% if method.name.starts_with?("_write_") %}
@@ -38,6 +42,7 @@ class BinaryParser
 
   macro uint32(name)
     property! :{{name.id}}
+    @{{name.id}} = 0u32
 
     def _read_{{name.id}}(io : IO)
       @{{name.id}} = io.not_nil!.read_bytes(UInt32).as(UInt32)
@@ -50,6 +55,7 @@ class BinaryParser
 
   macro uint16(name)
     property! :{{name.id}}
+    @{{name.id}} = 0u16
 
     def _read_{{name.id}}(io : IO)
       @{{name.id}} = io.not_nil!.read_bytes(UInt16).as(UInt16)
@@ -62,6 +68,7 @@ class BinaryParser
 
   macro uint8(name)
     property! :{{name.id}}
+    @{{name.id}} = 0u8
 
     def _read_{{name.id}}(io : IO)
       @{{name.id}} = io.not_nil!.read_bytes(UInt8).as(UInt8)
@@ -74,6 +81,7 @@ class BinaryParser
 
   macro int32(name)
     property! :{{name.id}}
+    @{{name.id}} = 0i32
 
     def _read_{{name.id}}(io : IO)
       @{{name.id}} = io.not_nil!.read_bytes(Int32).as(Int32)
@@ -86,6 +94,7 @@ class BinaryParser
 
   macro int16(name)
     property! :{{name.id}}
+    @{{name.id}} = 0i16
 
     def _read_{{name.id}}(io : IO)
       @{{name.id}} = io.not_nil!.read_bytes(Int16).as(Int16)
@@ -98,6 +107,7 @@ class BinaryParser
 
   macro int8(name)
     property! :{{name.id}}
+    @{{name.id}} = 0i8
 
     def _read_{{name.id}}(io : IO)
       @{{name.id}} = io.not_nil!.read_bytes(Int8).as(Int8)
@@ -110,6 +120,7 @@ class BinaryParser
 
   macro char(name)
     property! :{{name.id}}
+    @{{name.id}} = '\0'
 
     def _read_{{name.id}}(io : IO)
       @{{name.id}} = io.not_nil!.read_char
@@ -118,18 +129,24 @@ class BinaryParser
 
   macro type(name, klass)
     property! :{{name.id}}
+    @{{name.id}} = {{klass}}.new
 
     def _read_{{name.id}}(io : IO)
       {% raise "Must inhert BinaryParser" if  @type >= klass.resolve %}
       @{{name.id}} = io.read_bytes({{klass}}).as({{klass}})
     end
+
+    def _write_{{name.id}}(io : IO)
+      io.write_bytes(@{{name.id}}.not_nil!)
+    end
   end
 
   macro array(name, opt)
+    {% raise "Must have count and type" unless opt[:type] && opt[:count]  %}
     property! :{{name.id}}
+    @{{name.id}} = [] of {{opt[:type]}}
 
     def _read_{{name.id}}(io : IO)
-      {% raise "Must have count or type" unless opt[:type] && opt[:count]  %}
       {% if opt[:count].is_a?(NumberLiteral) %}
         @{{name.id}} = Array({{opt[:type]}}).new({{opt[:count]}}) do
           io.read_bytes({{opt[:type]}})
@@ -143,5 +160,35 @@ class BinaryParser
         # TODO: support :eof
       {% end %}
     end
+
+    def _write_{{name.id}}(io : IO)
+      @{{name.id}}.not_nil!.each do |item|
+        io.write_bytes(item)
+      end
+    end
+  end
+
+  macro string(name, opt = { count: -1 })
+    property! :{{name.id}}
+    @{{name.id}} = ""
+
+    def _read_{{name.id}}(io : IO)
+      {% if opt[:count] != -1 %}
+        slice = io.read({{opt[:count]}})
+        @{{name.id}} = String.new(slice)
+      {% else %}
+        @{{name.id}} = io.gets('\0')
+      {% end %}
+    end
+
+    def _write_{{name.id}}(io : IO)
+      {% if opt[:count] != -1 %}
+        slice = Slice(UInt8).new({{opt[:count]}})
+        slice.copy_from(@{{name.id}}.not_nil!.to_slice)
+        io.write(slice)
+      {% else %}
+        io.write(@{{name.id}}.not_nil!.to_slice)
+      {% end %}
+    end
   end
 end